<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>测试复制</title>
    <style type="text/css">
        .wrapper {position: relative;}
        #input {position: absolute;top: 0;left: 0;opacity: 0;z-index: -10;}
       </style>
</head>
<body>
    <div class="wrapper">
        <p id="text">我把你当兄弟你却想着复制我？</p>
        <textarea id="input">这是幕后黑手</textarea>
        <button onclick="copyText()">copy</button>
       </div>
</body>
</html>

<script type="text/javascript">
    function copyText() {
     var text = document.getElementById("text").innerText;
     var input = document.getElementById("input");
     input.value = text; // 修改文本框的内容
     input.select(); // 选中文本
     document.execCommand("copy"); // 执行浏览器复制命令
     alert("复制成功");
    }
    </script>